1. Field of the Invention
The present invention relates to a roller assembly for a belt conveyor and, more specifically, it provides a unitary co-injected annular seal which has a first labyrinth seal portion and a contact seal portion composed of a different material.
2. Description of the Prior Art
In connection with belt conveyors as used in mining and other industries, it has been known to provide a fixed shaft having an idler roller rotatably mounted with respect thereto and an interposed bearing which facilitates the relative rotation. See, generally, U.S. Pat. Nos. 3,984,160, 4,972,939, 5,188,214, 5,261,528, and 5,383,549.
It has also been known to provide labyrinth seals in idler rollers for conveyors. See, generally, U.S. Pat. Nos. 4,277,114, 4,919,253, 5,028,054 and 5,046,869.
U.S. Pat. Nos. 5,025,917 and 5,074,408 disclose conveyor roller tubes for belt conveyors which have a bearing interposed between the housing and end cover, a labyrinth seal, and a separate additional seal element disposed adjacent to the bearing.
U.S. Pat. No. 4,379,600 discloses a journal bearing with a dust seal wherein a deformable sealing ring in the form of a separate lip member is provided adjacent to a labyrinth seal and has one end received within a preformed groove.
U.S. Pat. No. 4,919,253 discloses a bearing lubrication system for an idler roller assembly for conveyors wherein a labyrinth seal, a bearing, and a felt seal are provided. See, also, U.S. Pat. Nos. 4,972,939, 5,188,214 and 5,261,528.
In spite of the foregoing known systems, there remains a need for an idler roller seal wherein the advantageous use of co-injection may be employed to provide a labyrinth seal of a first material integrally formed with a wiper or contact seal composed of a more flexible material which may be employed in an otherwise conventional idler roller construction.